This study will examine the effects of a tornado-related natural disaster on children and parents participating in an ongoing substance use prevention trial and will allow a unique opportunity to examine changes in children's and parents' predisaster and postdisaster functioning on a comprehensive range of biopsychic- social indicators and on substance abuse and mental health service use in an already at-risk sample. Research on the service use, substance use, behavioral and emotional effects of natural disasters on children and their caretakers has received limited empirical attention, even though such disasters have considerable public health significance due to increases in disordered emotional and behavioral functioning and service use demands. Existing studies of the aftereffects of natural disasters on children are limited by not knowing how much the disaster changed the children's predisaster functioning. This will be the first disaster study that includes extensive data on children's behavioral, emotional, (teacher, parent, peer, and self reports), social (children's peer relations based on peer, teacher and self report) and psycho- physiological (skin conductance, heart rate, respiratory sinus arrhythmia) functioning both before and after disaster exposure. Another important innovation of the proposed study is that it will follow a sample of preadolescent children identified as being at-risk prior to the disaster. Thus, the sample is likely to be more heavily influenced by the disaster (Kaminer et al., 2005; Resnick, 1995; Weems et al., 2010), because the tornado that devastated the study area adds another set of risk factors to already vulnerable children. The specific aims of the project are: 1 To explore changes in functioning pre-to-post tornado in children (emotional, behavioral, social, academic, and autonomic nervous system functioning and substance use) and primary caretakers (emotional functioning and parenting practices); 2) To explore moderation of changes in child and caretaker functioning pre-to-post tornado by degree of tornado exposure, by pre- tornado child (sex, ethnicity, temperamental anxiety) and family (socioeconomic status, post-tornado negative life events, levels of family social support, parenting practices) characteristics and by gene-by- environment (degree of exposure to the tornado) effects; 3) To explore moderation of post-tornado rates of substance abuse, mental health service use and diagnostic outcomes by degree of tornado exposure and pre-tornado child and family characteristics and by caretakers' and children's changes in functioning; 4) To determine whether cognitive behavioral intervention (Coping Power) delivered after the tornado (Cohort 3 versus Cohorts 1 and 2) attenuates increases in behavioral and emotional problems after the tornado in a transdiagnostic fashion. The funding sought here would make it possible to address these aims by supporting the assessment of the existing intervention sample at more frequent and longer-term time points and on additional measures linked to the specific aims.